The Use of The Fenton Preterm Growth Chart and Z-Scores as Growth Parameters in Assessing the Risk of Retinopathy of Prematurity
Ashlee M. Cerda, MPH; Brandie D. Wagner, PhD; Anne M. Lynch, MD; Jennifer L. Jung, MD; Erica Wymore, MD; Jasleen K. Singh, MD; Robert W. Enzenauer, MD; Emily A. McCourt, MD
University of Colorado School of Medicine
Introduction: Numerous studies have demonstrated the importance of weight gain in the preterm infant as a risk factor for ROP. The purpose of this study was to determine, using the z-score, if infants who negatively deviate from their growth curves have a higher risk of developing high-grade ROP (hg-ROP), Types 1 & 2. The z-score is a measure of deviation from the mean weight adjusted for gestational age.
Methods: We performed a retrospective review of 1025 infants who developed hg-ROP (2006 -August 2015). Z-scores for each infant’s birth and 28 day weight were calculated using the Fenton Preterm Growth Chart. The difference in z-scores over the 4 week period was determined. Data were categorized to the following change in z-score deviation (dev) groups: 0-0.5 dev, 0.6-0.9 dev, 1-1.4 dev, 1.5-1.9 dev, and > 2 dev. The incidence of hg- ROP was assessed using trend analysis and logistic regression.
Results: In the 129 (12.6%) infants who developed hg-ROP, the median (range) deviation was -0.91(-2.81-(-0.01)). Incidence of hg-ROP among the deviation groups were: 20 (10.8%), 46 (10.3%), 45 (14.8%), 14 (18.9%), and 4 (26.7%), respectively (p < 0.01). Infants with > 2 deviations were 1.93 times more likely to develop hg-ROP than patients who deviated 0- 0.5 from their growth curve (OR: 1.93 95% Cl: 0.91-4.05 p=0.08)
Discussion: There was a dose-response trend in the incidence of hg-ROP as deviation scores increased.
Conclusion: Infants who deviate from their growth curve have a higher risk of developing high-grade ROP and should be closely monitored.
References: Fenton TR, Kim JH. A systematic review and meta-analysis to revise the Fenton growth chart for preterm infants. BMC Pediatr. 2013; 13(1):59.